So, uh. Spire blade spawners? Are... ridiculous? Maybe?
I just had a ten pack of them (Mark 3 & 4, though it could have been done with 2 & 3... or even just one mark's cap alone, I imagine, though it would have took longer. Mark 1 was out due to ion cannon , heh.) basically solo, so to speak, a mark four AI system (level... 6? Difficulty, I think.). There were some spire frigates running interference, but... it could have been done pretty easily without them.
The big thing is that they're like mobile million+ HP sniper turrets with limited close combat capability... and a much, much bigger punch. 50k/mark at not-infinite-but-might-as-well-be range and pretty decent rate of fire. Critters swatted down guard posts and whatnot on the opposite side of the system while idling out in the yellow band. S'crazy. Goes through shields (and is unaffected by the spawner being under a shield, as near as I can tell.), basically infinite armor pen, moves faster than almost any projectile in the game... sure, the blades can technically be shot down (and spire maws love to eat them, which is somewhat amusing), but in practice nothing can kill them fast enough to matter unless it's at the very extreme range of the blade's lifetime. And the spawners themselves have a bit of a kick to them, as well as being decently quick and pretty tough.
I guess I'm just saying I love these little guys and they're the most awesome of awesome things.